The Efficiency Method
1. Assume Total Work = LCM of all given time values.
2. Efficiency (work/day) = Total Work ÷ number of days.
3. Combined efficiency = sum of individual efficiencies. Time = Total Work ÷ Combined Efficiency.
💡 Example: A finishes work in 12 days, B in 18 days. Total work = LCM(12,18)=36. A's rate=3/day, B's rate=2/day. Together: 36/5 = 7.2 days.
Work-Wages Rule
Wages are divided in the ratio of EFFICIENCY (work done), not in the ratio of days taken.
- For "A and B start together, A leaves after some days" problems: calculate work done together up to that point, then let the remaining person finish the rest alone.